Hollow urchin-like NiO/NiCoO heterostructures as highly efficient catalysts for selective oxidation of styrene.

Three-dimensional (3D) hierarchical hollow urchin-like NiO/NiCoO heterostructures have been prepared via a facile one-pot hydrothermal method. The 3D urchin-like structure brings about high specific surface area of 40.2 m g. The NiO/NiCoO heterostructures are composed of 59 wt% of NiO and 41 wt% of NiCoO and enriched with NiO-NiCoO phase boundaries. When used as catalysts for styrene oxidation reaction (SOR), the NiO/NiCoO heterostructures present a markedly high selectivity of 90.8% to styrene oxide (SO) and a high SO yield of 81.4%. The high catalytic performance of the NiO/NiCoO heterostructures can be attributed to the high specific surface area and the abundant NiO-NiCoO phase boundaries, both of which contribute to the numerous active sites.